Mr Corbyn's last-minute decision to take part in the BBC debate in Cambridge was created to wrong-foot Ms May by portraying her as running scared of a confrontation with him.
Mrs May faced accusations of "extreme cowardice" as the Tories confirmed they would be represented by Home Secretary Amber Rudd, while other parties send their leaders - or in the case of the Scottish National Party, its leader in Westminster.
However, that did not keep the other party leaders from criticizing her decision to dodge their grilling.
Liberal Democrat leader Tim Farron slammed the Prime Minister for "running away" from the debate on Wednesday evening.
Sterling weakened against the dollar late Wednesday after the YouGov poll but was trading at 1.2862 early on Thursday, 3 cents above where it was trading at the start of the campaign.
"I have never been afraid of a debate in my life".
"The Tories have been conducting a stage-managed arms-length campaign and have treated the public with contempt".More news: Spain and India PMs meet to boost economic, security ties
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"Refusing to join me in Cambridge tonight would be another sign of Theresa May's weakness, not strength", he said.
Amber Rudd accidentally let her poor knowledge of the rules of Monopoly slip when criticising Jeremy Corbyn over his "fantasy economics".
Plaid Cmyru leader Leanne Wood added: "It's appalling leadership on behalf of the prime minister who can't even be bothered to come here and answer these questions for herself".
Jeremy Corbyn, her opponent in the race for Number 10, will also be campaigning on Brexit, buoyed by an opinion poll which suggested the Tory lead had been reduced to just three points. And why do you think she called this election?
During a Q&A at a factory in Bath, May was asked by journalists if she was "frightened" about facing Corbyn in a head-to-head debate, to which she replied: "No. Jeremy Corbyn seems to be paying far more attention to how many appearances on television he's doing".
As Corbyn noted, the prime minister had agreed to participate in the televised town hall hosted by Channel 4 News and Sky on Monday, but only on the condition that she not be on stage at the same time as her rival.
But Conservatives dismissed Mr Corbyn's figures as "dodgy", pointing to official statistics showing falling NHS waiting times and hospital deficits, as well as their own manifesto promise to increase real-terms spending on schools.